package UDPEcho;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

public class UDPEchoSever1 {
    //UDP的Socket
    private DatagramSocket socket = null;

    public  UDPEchoSever1(int port) throws SocketException {
        socket = new DatagramSocket(port);
    }

    public  void start() throws IOException {
        System.out.println("服务器启动！");
        while(true) {
            //接收并解析客户端发来的请求
            DatagramPacket requestPacket = new DatagramPacket(new byte[4096], 4096);
            socket.receive(requestPacket);
            String request = new String(requestPacket.getData(), 0, requestPacket.getLength());
            //根据请求构造响应
            String response = process(request);
            //将响应返回给客户端
            DatagramPacket responsePacket = new DatagramPacket(response.getBytes(), 0, response.getBytes().length, requestPacket.getSocketAddress());
            socket.send(responsePacket);
            //打印日志
            System.out.printf("[%s:%d] req:%s resp:%s", requestPacket.getSocketAddress(), requestPacket.getPort(), request, response);
        }
    }

    private String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        UDPEchoSever1  udpEchoSever1 = new UDPEchoSever1(6060);
        udpEchoSever1.start();
    }
}
